Chaetura cinereiventris
Silhouette: Aviceda (vectorized by T. Michael Keesey) · PhyloPic
In 3 days ~10% in a week ~20%
The grey-rumped swift or gray-rumped swift (Chaetura cinereiventris) is a species of bird in subfamily Apodinae of the swift family Apodidae. It is found in Honduras, Nicaragua, Costa Rica, and Panama; in every mainland South American country except Chile, French Guiana, Suriname, and Uruguay; in Trinidad and Tobago; and on Grenada.
The grey-rumped swift, pale-rumped swift (C. egregia), band-rumped swift (C. spinicaudus), and Lesser Antillean swift (C. martinica) were at one time placed in genus Acanthylis. Some authors have suggested that the grey-rumped and pale-rumped swifts are conspecific. Others have suggested that all of the grey-rumped subspecies except the nominate C. c. cinereiventris belong to another species under the binomial C. sclateri.
The grey-rumped swift is about 10.5 cm (4.1 in) long and weighs about 17 g (0.60 oz). It has... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Santa Cruz de la Sierra | 🇧🇴 Bolivia | |
| 2 | Rio de Janeiro | 🇧🇷 Brazil | |
| 3 | Manaus | 🇧🇷 Brazil | |
| 4 | Guayaquil | 🇪🇨 Ecuador | |
| 5 | São Paulo | 🇧🇷 Brazil |
Rare
Under 5% of wildlife watchers report a Gray-rumped Swift sighting in Bastimentos Island National Marine Park on a given day, based on 120 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 201st most-seen of the 375 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
October to December
In those months about 10% of wildlife watchers report a Gray-rumped Swift in Bastimentos Island National Marine Park on a given day, against under 5% in January to September, the lowest months.
Between 3 and 6 pm
Across all the parks we cover, that three-hour window holds the most Gray-rumped Swift sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
16th of 32
Of the 32 parks where we can rate Gray-rumped Swift sightings, Bastimentos Island National Marine Park ranks 16th at under 5%. The best odds are in Serra dos Órgãos National Park (Brazil, about 50%), Main Ridge Forest Reserve (Trinidad and Tobago, about 20%) and Tortuguero National Park (Costa Rica, about 20%). All parks ranked.
GBIF citizen-science records
It is estimated from how often the Gray-rumped Swift is recorded against all the birds logged in Bastimentos Island National Marine Park (120 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
